Explore Dr. Retzler’s HormoneSynergy® Longevity Medicine Resource Library

Longevity Medicine, Functional Wellness & Anti-Aging Insights from HormoneSynergy®

Welcome to the HormoneSynergy® Longevity Medicine Blog, a physician-guided clinical library led by Dr. Kathryn Retzler. Our articles cover the systems that most often shape health with age: metabolic health, hormones, cardiovascular and kidney risk, body composition, bone and muscle, brain health, sleep, gut health, nutrition, supplements, and the biology of aging.

The library is organized around clinical questions rather than trends. Some articles review new research. Others explain testing, treatment, nutrition, or a condition patients commonly encounter. Across the collection, the standard is the same: evidence first, appropriate uncertainty, and enough clinical context to separate useful medicine from wellness marketing.

Start with the HormoneSynergy® Longevity Medicine Framework

New & recently updated:

Metabolic Health & Insulin Resistance

Clinical resources on insulin resistance, glucose regulation, metabolic syndrome, visceral fat, prediabetes, obesity and GLP-1-based care within a broader longevity medicine plan.

Kidney Health & Cardiovascular-Kidney-Metabolic Health

Kidney health belongs in the same clinical conversation as blood pressure, diabetes, insulin resistance, obesity and cardiovascular risk. These resources cover early detection, CKD, albuminuria, nutrition and CKM health.

Gut Health, Microbiome & Immune Signaling

Clinical education on the microbiome, intestinal barrier, fiber, inflammation, gut-brain signaling, immune biology and the growing connections between gut, metabolic and kidney health.

Food Quality, Vitamins, Supplements & Wellness Claims

Evidence-based guidance on nutrient gaps, supplement quality, interactions, food claims and longevity products, with an emphasis on where supplementation helps and where marketing outruns the evidence.

  • What Is the Best Form of Glutathione? Oral, Liposomal, S-Acetyl, IV and Precursors

    Clinician explains oral, liposomal, S-acetyl and IV glutathione alongside NAC and glycine precursor support.

    Reduced, liposomal and S-acetyl glutathione deliver glutathione differently, while NAC and glycine support the body’s own production. IV glutathione bypasses digestion but introduces additional risks. Here is how the major forms compare and what the evidence actually supports.

  • The Most Effective Weight Loss Method: GLP1 Agonists Explained - Dr. Kathryn Retzler, Lake Oswego Oregon

    The Most Effective Weight Loss Method: GLP1 Agonists Explained - Dr. Kathryn Retzler, Lake Oswego Oregon
    GLP-1 agonists have gained attention not only for their effectiveness in managing blood sugar levels in diabetes but also for their potential as we...
  • Weight Loss Doctor Lake Oswego Oregon - GLP-1 Agonists

    Weight Loss Doctor Lake Oswego Oregon - GLP-1 Agonists
    GLP-1 (glucagon-like peptide-1) agonists are a class of medications used in the treatment of type 2 diabetes mellitus. They work by mimicking the a...
  • What Longevity Medicine Can - and Cannot - Do

    What Longevity Medicine Can -  and Cannot -  Do

    The goal of longevity medicine is not to stop aging or turn a 65-year-old back into a 35-year-old. It is to find important risk earlier, preserve muscle, bone, cardiovascular and cognitive health, and protect the ability to remain active and independent as the years accumulate.

  • Looking for a Functional Medicine Doctor? Why We Practice Preventive Longevity Medicine Instead

    Patients discussing Preventive Longevity Medicine and individualized healthy-aging care with a physician at HormoneSynergy.

    Many people searching for a functional medicine doctor are looking for something quite reasonable: more time, a broader medical history, attention to lifestyle and a physician willing to look beyond an isolated symptom. Much of that still describes the way we practice. What has changed is the name and, more importantly, the emphasis. At HormoneSynergy, we call it Preventive Longevity Medicine.

  • Mental Health Is Longevity Medicine: Where Integrative Psychiatry Fits

    Woman discussing mental health and healthy aging with a physician as part of a preventive longevity medicine assessment.

    We talk easily about cholesterol, glucose, muscle and bone when we discuss longevity. Mental health deserves the same attention. Depression, anxiety, chronic stress, poor sleep and social isolation do not stay neatly confined to the mind. A thoughtful longevity strategy has to consider the brain, the body and the life a person is actually living.

  • Total Gut Restoration by Microbiome Labs

    Total Gut Restoration by Microbiome Labs
    Recondition Reinforce Rebuild™ by Microbiome LabsTotal Gut Restoration is an advanced 3-month protocol to support and restore gut health. A triple-...
  • Tri-Fortify Liposomal Glutathion and ATP 360 by Researched Nutritionalse and ATP 360 by Researched Nutritionals

    Tri-Fortify Liposomal Glutathion and ATP 360 by Researched Nutritionalse and ATP 360 by Researched Nutritionals
    We are pleased to share with you the recording and slides from Dr. Christopher Wakely's presentation: Potentiate Peptide and Hormone Therapy by Tar...
  • Longevity Medicine Has Grown Up: What Actually Matters Now

    Longevity Medicine Has Grown Up: What Actually Matters Now

    Longevity medicine used to be described as “anti-aging”: restore youthful hormones, protect telomeres, stimulate mitochondria and try to slow the clock. Some of that biology remains fascinating. But good longevity medicine has become much more practical. The real work is finding disease earlier, preserving muscle and bone, protecting the brain and cardiovascular system, and helping people remain capable as they age.

  • DEXA Scan in Portland & Lake Oswego: What It Tells You

    DEXA Scan in Portland & Lake Oswego: What It Tells You

    A DEXA scan reveals much more than body weight. It precisely measures bone density, visceral fat, and lean muscle—providing a clear picture of true body composition. Learn how DEXA helps guide personalized strength, metabolic, and longevity planning in Portland and Lake Oswego, and why this test is more useful than a scale alone.

  • Full-Body MRI Can Find More. That Doesn't Mean It Finds What Matters.

    Full-body MRI scanner representing the benefits and limitations of elective MRI screening in preventive longevity medicine.

    A full-body MRI can produce an extraordinary amount of information without exposing you to ionizing radiation. It can also uncover abnormalities that were never going to hurt you. The real question isn't whether the scan can find something. It's whether finding it improves your health.

  • Semaglutide Integrative Weight Loss in Portland Oregon

    Semaglutide Integrative Weight Loss in Portland Oregon
    Semaglutide and tirzepatide are medications initially developed to treat type 2 diabetes but are now FDA-approved to treat obesity. When used for weight loss, a semaglutide or tirzepatide weight loss program involves a once-weekly injection of the drug.